The thigh muscles are divided into three groups. The anterior group is the flexors, the posterior group is the extensors, and the medial group is responsible for adducting the thigh. They have a significant mass and length, act on the hip and knee joints, performing a static and dynamic function when moving or standing. Like the muscles of the pelvis, the muscle fibers of the lower extremities reach their maximum development, which can be associated with upright posture.
Tailor's muscle location
This muscle (musculus sartorius) is the longest among the muscle fibers of the body. In the proximal part, it is attached to the superior iliac spine and descends obliquely along the front surface of the thigh. The peculiarity is that at the same time it is directed from outside to inside and forms a kind of crypt in the gunter's canal over the femoral artery, saphenous nerve and vein.
At the bottom of the thigh, the sartorius runs almost vertically and crosses the medial condyle. In the distal region, it ends with a tendon, attaching to the fascia of the lower leg.
Features of the tailor's muscle
This muscle got its name because of its participation in the movements of the hip joint, in whicha person can acquire the pose of a cross-legged tailor (the word "sartor" is translated as "tailor").
The tendons of musculus sartorius, together with the tendons of the thin and semitendinous muscle fibers, form a fibrous triangular plate, which is called the "crow's foot".
It is worth noting that the sartorius muscle refers to fibers that are capable of significantly changing their length during contraction. The rectus abdominis muscle, as well as the thin and semitendinosus muscle, still have a similar property. A feature of the fibers of the sartorius muscle is that they do not form clear bundles. This leads to the fact that their neuromuscular synapses are characterized by an unusual distribution. In addition, the sartorius muscle can divide into two parallel bellies or be crossed by a tendon constriction, which leads to its division into an upper and lower part.
It should also be mentioned that this muscle is clearly visible under the skin if the thigh is bent or abducted, as well as in cases where the lower leg is extended. In addition, it is well palpated in the upper thigh area.
Role of the sartorius
Musculus sartorius is involved in hip flexion and abduction, and this muscle is responsible for outward rather than inward movements. With internal rotation of the hip, it is not involved. When trying to carry out external rotation, it either does not activate at all, or is activated incompletely. In the sitting position, external rotation of the sartorius muscle is accompanied by moderate activity. When bending the knee joint, this muscle fiber is activated more actively if at the same timeundergoes hip flexion.
It should be noted that the EMG examination revealed that the sartorius muscle is actively working when playing volleyball or basketball. At the same time, the musculus sartorius on the left side is activated more actively during any movements with the right hand (for example, while playing tennis), and also works when walking, jumping or cycling.
Thus, along with other muscle fibers, the sartorius muscle, whose functions include movement of the lower limbs, provides outward rotation of the thigh, and is also responsible for flexion of the lower leg.
Innervation of the sartorius muscle
The femoral nerve, which consists of 2-4 roots, is responsible for the innervation of the musculus sartorius. Branches of this nerve innervate the skin of the inner surface of the thigh and the medial region of the leg to the edge of the foot.
With pathological changes in the femoral nerve, paresis or paralysis may develop, as well as a decrease in tone or tendon reflexes. Prolonged muscle paralysis leads to muscle atrophy and contractures, which are accompanied by pathological limb placement through the activation of he althy antagonist muscles.
In addition, there may be sensory disturbances in the form of paresthesia, hypoesthesia, or complete anesthesia. Sometimes, on the contrary, a change in sensitivity is recorded according to the type of hyperpathy, when patients develop pains of a burning nature that are not relieved by analgesics.
When the innervation of the sartorius muscle is disturbed, asas a rule, walking is disturbed, which can be explained by difficulties in flexing the lower limb in the hip joint or the impossibility of normal lifting of the hip.
What to do if the sartorius muscle is damaged?
Neuropathy of the femoral nerve, which impairs the contractility of the sartorius muscle, most often develops after surgery in the pelvic organs or the hip. The cause can also be stretching or direct compression of the muscle fibers. It is also worth mentioning that neuropathy can occur against the background of diabetes.
If there are signs of damage to the femoral nerve, which is accompanied by impaired flexion of the lower limb, you should contact a neurologist. He will conduct a neurological examination, electrodiagnostics, if necessary, prescribe computed tomography, MRI of the retroperitoneal space, as well as appropriate treatment.
When the sartorius femoris is damaged, drug therapy is effective. The method of relaxation and stretching of the affected muscle fibers, blockade of the femoral nerve and correction of excessive leg extension and changes in the length of the lower limb due to the development of contractures are also used. It should be noted that a positive result can only be obtained by correcting the work of muscles that are functionally related to the affected area.
